Screening and Analysis for Efficient Co-inoculation System of Soybean Rhizobia and Plant Growth-promoting Rhizobacteria

Plant growth promoting rhizobacteria(PGPR)were screened from soybean rhizosphere soil and collected strains through qualitative analysis of phosphate solubilization and IAA.Five PGPR strains were acquired,which improved nodulation on soybean when co-inoculated with soybean rhizobia in vermiculite pot experiment.Furthermore in the soil pot experiment with Fuyang,Jining and Yanan's soils,the co-inoculation of soybean rhizobia with five PGPR strains significantly increased the number of nodules,nodule dry weight,plant dry weight,total N and P contents.The result of quatitive determination of phosphate displayed that five PGPR strains dissolved inorganic phosphorus efficiently.Analysis of fermentation with HPLC showed that 5 isolated strains secreted plant hormones and organic acids.Through 16S rRNA gene sequence analysis,three PGPR 1-3,P7 and P13 strains isolated from soybean rhizosphere soil were belonged to Bacillus sp.,Phyllobacterium sp.and Sinorhizobium sp.,respectively.